Risk factors for pulmonary mucormycosis in subjects with diabetes mellitus-A case-control study

Sensitivity and Specificity of Plasma and Bronchoalveolar Lavage Fluid PCR for Diagnosing Pulmonary Mucormycosis in Subjects With Diabetes Mellitus

BACKGROUND

Mucorales polymerase chain reaction (PCR) is used to diagnose pulmonary mucormycosis (PM) among neutropenic individuals. However, data on the utility of PCR in patients with diabetes mellitus, another major risk factor for PM, are limited.

OBJECTIVE

The primary objective was to assess the diagnostic performance of a commercial real-time PCR assay (MucorGenius) in plasma and bronchoalveolar lavage fluid (BALF) for diagnosing PM (proven and probable cases only) in patients with suspected invasive mould disease (IMD). For the secondary objective, we evaluated the performance of the MucorGenius assay in all PM (proven, probable, and possible) cases.

METHODS

We prospectively enrolled patients with suspected IMD and assessed the performance of MucorGenius PCR (index test) in plasma and BALF samples. A multidisciplinary team assigned the final diagnosis of IMD (reference standard) based on microscopy, histopathology, cytology, and culture. We report the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) with 95% confidence intervals (CI).

RESULTS

We enrolled 103 patients, of whom 43 (41.7%) were confirmed to have PM. Plasma PCR showed a sensitivity of 18.6% (95% CI: 8.4-33.4), specificity of 90.7% (95% CI:77.9-97.4), PPV of 66.7%, and NPV of 52.7%. Including possible PM/IMD cases improved the plasma PCR sensitivity to 30.0% (95% CI: 18.9-43.2) and retained specificity at 90.7%. BALF PCR had better sensitivity (47.4%) but poorer specificity (69.6%), with a PPV of 56.3% and NPV of 61.5%.

CONCLUSION

Plasma and BALF MucorGenius PCR have poor diagnostic performance for diagnosing PM among individuals with diabetes mellitus. Further multicenter studies are needed to validate these findings.

Iron Levels in Bronchoalveolar Lavage Fluid of Hematological Patients with Suspected Invasive Pulmonary Aspergillosis and their Association with 12-week Mortality: A Retrospective Cohort Study

OBJECTIVES

Accuracy of diagnostic tests for invasive pulmonary aspergillosis (IPA) using bronchoalveolar lavage fluid (BALF) remains suboptimal. Elevated tissue iron in lung transplant and murine models is linked to invasive Aspergillus growth. This study examines the correlation between BALF iron levels, IPA, and 12-week mortality.

METHODS

We conducted a retrospective cohort study at a tertiary care center, including 100 BALF samples from patients with hematological malignancies and suspected IPA between 2014 and 2019. Data regarding iron concentrations, mycological tests, and 12-week mortality were analyzed.

RESULTS

Higher iron levels correlated with a greater likelihood of IPA based on EORTC/MSGERC 2020 definitions (p = 0.038). The ROC area was 0.648 (95% CI 0.531-0.764), with an optimal cut-off of 0.75 µmol/L to distinguish cases (27 probable and 0 proven IPA) from controls (56 possible and 17 no IPA), with sensitivity 76.9% and specificity 47.3%. Iron levels were positively correlated with higher fungal loads (galactomannan: Spearman's ρ 0.323, p = 0.001; Aspergillus PCR Ct-values: ρ - 0.602, p = 0.002). A trend toward higher 12-week mortality was observed in patients with iron concentrations ≥ 0.90 µmol/L compared to lower levels (p = 0.086).

CONCLUSIONS

BALF iron concentrations were highest in those with probable IPA, followed by possible IPA and lowest in patients without IPA, with higher iron levels also correlating with fungal loads and potentially with 12-week mortality. However, given the various potential confounding factors, further prospective studies are essential to establish causality. These findings warrant additional investigation into BALF iron as a potential marker for 12-week survival, but validation is necessary before considering it as a supplementary marker in the current EORTC/MSGERC 2020 classification for probable or possible IPA.

Prevalence of co-existent COVID-19-associated pulmonary aspergillosis (CAPA) and its impact on early mortality in patients with COVID-19-associated pulmonary mucormycosis (CAPM)

BACKGROUND

Data on mixed mould infection with COVID-19-associated pulmonary aspergillosis (CAPA) and COVID-19-associated pulmonary mucormycosis (CAPM) are sparse.

OBJECTIVES

To ascertain the prevalence of co-existent CAPA in CAPM (mixed mould infection) and whether mixed mould infection is associated with early mortality (≤7 days of diagnosis).

METHODS

We retrospectively analysed the data collected from 25 centres across India on COVID-19-associated mucormycosis. We included only CAPM and excluded subjects with disseminated or rhino-orbital mucormycosis. We defined co-existent CAPA if a respiratory specimen showed septate hyphae on smear, histopathology or culture grew Aspergillus spp. We also compare the demography, predisposing factors, severity of COVID-19, and management of CAPM patients with and without CAPA. Using a case-control design, we assess whether mixed mould infection (primary exposure) were associated with early mortality in CAPM.

RESULTS

We included 105 patients with CAPM. The prevalence of mixed mould infection was 20% (21/105). Patients with mixed mould infection experienced early mortality (9/21 [42.9%] vs. 15/84 [17.9%]; p = 0.02) and poorer survival at 6 weeks (7/21 [33.3] vs. 46/77 [59.7%]; p = 0.03) than CAPM alone. On imaging, consolidation was more commonly encountered with mixed mould infections than CAPM. Co-existent CAPA (odds ratio [95% confidence interval], 19.1 [2.62-139.1]) was independently associated with early mortality in CAPM after adjusting for hypoxemia during COVID-19 and other factors.

CONCLUSION

Coinfection of CAPA and CAPM was not uncommon in our CAPM patients and portends a worse prognosis. Prospective studies from different countries are required to know the impact of mixed mould infection.

Risk factors, mortality, and predictors of survival in COVID-19-associated pulmonary mucormycosis: a multicentre retrospective study from India

OBJECTIVES

To compare COVID-19-associated pulmonary mucormycosis (CAPM) with COVID-19-associated rhino-orbital mucormycosis (CAROM), ascertain factors associated with CAPM among patients with COVID-19, and identify factors associated with 12-week mortality in CAPM.

METHODS

We performed a retrospective multicentre cohort study. All study participants had COVID-19. We enrolled CAPM, CAROM, and COVID-19 subjects without mucormycosis (controls; age-matched). We collected information on demography, predisposing factors, and details of COVID-19 illness. Univariable analysis was used to compare CAPM and CAROM. We used multivariable logistic regression to evaluate factors associated with CAPM (with hypoxemia during COVID-19 as the primary exposure) and at 12-week mortality.

RESULTS

We included 1724 cases (CAPM [n = 122], CAROM [n = 1602]) and 3911 controls. Male sex, renal transplantation, multimorbidity, neutrophil-lymphocyte ratio, intensive care admission, and cumulative glucocorticoid dose for COVID-19 were significantly higher in CAPM than in CAROM. On multivariable analysis, COVID-19-related hypoxemia (aOR, 2.384; 95% CI, 1.209-4.700), male sex, rural residence, diabetes mellitus, serum C-reactive protein, glucocorticoid, and zinc use during COVID-19 were independently associated with CAPM. CAPM reported a higher 12-week mortality than CAROM (56 of the 107 [52.3%] vs. 413 of the 1356 [30.5%]; p = 0.0001). Hypoxemia during COVID-19 (aOR [95% CI], 3.70 [1.34-10.25]) and Aspergillus co-infection (aOR [95% CI], 5.40 [1.23-23.64]) were independently associated with mortality in CAPM, whereas surgery was associated with better survival.

DISCUSSION

CAPM is a distinct entity with a higher mortality than CAROM. Hypoxemia during COVID-19 illness is associated with CAPM. COVID-19 hypoxemia and Aspergillus co-infection were associated with higher mortality in CAPM.

Immune and metabolic perturbations in COVID-19-associated pulmonary mucormycosis: A transcriptome analysis of innate immune cells

BACKGROUND AND OBJECTIVES

The mechanisms underlying COVID-19-associated pulmonary mucormycosis (CAPM) remain unclear. We use a transcriptomic analysis of the innate immune cells to investigate the host immune and metabolic response pathways in patients with CAPM.

PATIENTS AND METHODS

We enrolled subjects with CAPM (n = 5), pulmonary mucormycosis (PM) without COVID-19 (n = 5), COVID-19 (without mucormycosis, n = 5), healthy controls (n = 5) without comorbid illness and negative for SARS-CoV-2. Peripheral blood samples from cases were collected before initiating antifungal therapy, and neutrophils and monocytes were isolated. RNA sequencing was performed using Illumina HiSeqX from monocytes and neutrophils. Raw reads were aligned with HISAT-2 pipeline and DESeq2 was used for differential gene expression. Gene ontology (GO) and metabolic pathway analysis were performed using Shiny GO application and R packages (ggplot2, Pathview).

RESULTS

The derangement of core immune and metabolic responses in CAPM patients was noted. Pattern recognition receptors, dectin-2, MCL, FcRγ receptors and CLEC-2, were upregulated, but signalling pathways such as JAK-STAT, IL-17 and CARD-9 were downregulated; mTOR and MAP-kinase signalling were elevated in monocytes from CAPM patients. The complement receptors, NETosis, and pro-inflammatory responses, such as S100A8/A9, lipocalin and MMP9, were elevated. The major metabolic pathways of glucose metabolism-glycolysis/gluconeogenesis, pentose phosphate pathway, HIF signalling and iron metabolism-ferroptosis were also upregulated in CAPM.

CONCLUSIONS

We identified significant alterations in the metabolic pathways possibly leading to cellular iron overload and a hyperglycaemic state. Immune responses revealed altered recognition, signalling, effector functions and a pro-inflammatory state in monocytes and neutrophils from CAPM patients.